I have a philips flat screen tv. Model 37FD9954/17s.I had a power serg and the tv went out.I replaced the power supply box.After testing the old one with voltage tester. It was blown.Installed the new one and the tv come on, but only stay's on about 5 minutes then it starts getting lighter and darker then goes black and then the sound goes out.The little power light starts blinking really fast.Then it take several tries over and over of turning it on and off to come on again. Only to do the same thing.Could you tell me whatelse it could be?
Power supply again? Inverter board? Main board?
Cold, Set both the contrast and brightness way down, 33% or so, and see if it stays on longer than 5 min., if so that is a clue that the problem may be heat related.
Without an isolation transformer or special test equipment you can do some basic checks, unplugged.
Recheck all connectors and ribbons.
Power supply, pull board, do a visual for swollen caps, test caps with ohmmeter, look for bad solder, test diodes and fet's for shorts.
Inverter, pull board, do same checks, also compare transformers with ohmmeter, resolder transformers.
Main board, pull board, look for bad solder. After the set shuts down, check where the heat is coming from, possibly from under a heatsink, from a small scale ic that may be too small to hand solder and needs to be reflowed.